Bike Material of the Future: Wood

Four seniors at Cedarville University in Cedarville, Ohio, are building and testing wooden bicycles for a capstone engineering project. The team’s capstone instructor, Jay Kinsinger, assistant professor of mechanical and biomedical engineering, shares his students’ interest in wooden bikes. Kinsinger has been building wooden bikes for four years, riding them across America and Europe. He built a folding tandem wooden bike that is on display at the Bicycle Museum of America in New Bremen, Ohio.

According to Kinsinger, wooden bicycle frames are tough, lightweight, and beautiful, with infinite design possibilities. He noted that the bikes get attention because they look different, but more importantly, it’s the smooth ride and the fun of building the bikes that captures the students’ imagination. “They are beautiful, but that's the least important reason to build one. They’re nice to ride, since wood dampens the road vibration,” Kinsinger told Design News. “The wooden bikes are comparable to an aluminum or lightweight steel bike.”

Senior engineering students Jake Miller, David Yoder, and Gerrit Start work on wooden bike frames for their capstone team project at Cedarville University. (Source: Scott Huck)

Currently, the student team is using walnut to build their bikes. “Walnut is a stable wood, and it has been used for centuries for gunstock. But walnut is not the only wood we could use,” Kinsinger told us. “There are strength and weight considerations in choosing the wood. Some woods, like cedar, split easily. Cedar is inherently going to split. That’s good for shingles, but not for bikes. Some woods are heavier than walnut. They can be like a brick.” Price is another consideration when selecting wood for the bikes. “Walnut is not expensive where we’re from. They sell it for $4 a square foot,” he said.

Kinsinger also noted the bikes are not difficult to build. “Anyone could build one. You use common shop tools. It’s within the reach of the woodworker,” he said. The important part of the project is for students to apply engineering tools in new ways to meet the challenge of creating a strong, durable bike. “Their engineering work is intended to eliminate guesswork from the building process. Each frame takes hundreds of hours to build, and weaknesses may easily remain hidden.”

Jay Kinsinger prepares to ride his wooden bike from the University of Dayton to the University of Notre Dame (238 miles). He was part of a team of riders from Cedarville University who were supporting the pro-life work of the Life Resource Center in Dayton, Ohio. (Source: Mark D. Weinstein)

The students conduct extensive tests on materials to avoid hidden weaknesses. The team sends completed frames to a bicycle test lab for further tests of strength. The point of the project for the students is to develop engineering skills, not to build bikes for their own use. “These mechanical engineering students are making test bikes that we will destroy in the process of testing them,” said Kinsinger. “They have developed the skills to build the bike, but they’re not necessarily building their own bikes for the course. They do take away the skills to build their own bikes, though.”

For Kinsinger, the value of the course is the testing experience it provides for students. “It’s a real-world situation, so there are no answers at the back of a textbook. Students have to create their own testing,” he said. “That stretches them their capabilities. They learn that engineering has to be a creative endeavor. They have to evaluate the material. Wood varies in a 3D way. It’s a challenge to evaluate wood.”

Using Epoxy resins to saturate wood and give it desired engineering characteristics has been done for decades. Before Epoxy, resorcinol glues were used to make airplane wings and propellors, and of-course boats. Some of the early wind power propellors were made of wood veneers as they were lighter and their performance could be very accurately predicted. Not sure flexibility is a desirable characteristic in a bicycle frame though. Wood saturated with epoxy is probably as dimensionally stable as any other material in regards to environmental changes. The difficulty is doing it the same every time.

Rob, while your title calls it a Material of the Future (I get it, spoken tongue in cheek) there was one line I specifically noted which guarantees this initiative will never launch as tomorrow's material of choice: "Each frame takes hundreds of hours to build". This is a beautiful hobbyist project, and they do look like a fun garage project; but I'm missing the point of why it's being developed at a University.

Given the right wood, adhesives and coatings, there's no reason to be sceptical about wooden bike frames. We've been building wood-framed (and some plywood-skinned) aircraft for over a century now, with great success. A comparable engineering challenge, perhaps, with weight, strength and complexity well within our abilities. Wooden boats have perhaps more latitude with weight, but greater requirement for the right water-resistant coatings and adhesives.

Agreed, it's a beautiful material, but I worry about moisture and then the lack of it. This Winter has been so awful that I have three guitars in the shop for cracks. Two of them are over forty years old and have never had humidty problems before.

Interesting idea Rob. These bikes would definitely dampen the road vibrations and look beautiful on the tracks, but what worries me is the deterioration of wood. We all know it is a hygroscopic material and it will be affected by vapors and other environmental factors. Will the design be able to cater these environmental influences? Because if not, these bicycle frames could be seriously damaged with absorption of moisture and deformation of wood.

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